Abstract

Background

Techniques for embryo transfer (ET) are being developed, optimized, and standardized to provide the best outcomes.This includes methods to reduce the risk of embryo loss following ET.

Objectives

To systematically locate, analyse, and review the best available evidence regarding the effectiveness of post-ET techniques for women undergoing in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI).

Search methods

Selection criteria

Screening and selection of 2436 possible trial citations were performed independently by two review authors. Four prospective, truly randomised trials met the inclusion criteria. The trials compared two competing post ET interventions or an intervention versus no treatment in women undergoing IVF and ICSI.

Data collection and analysis

Two review authors independently collected data and assessed risk of bias using a standardized data extraction form. Individual outcome data were extracted to support an intention-to-treat analysis.

Main results

The primary outcome, live birth rate, was not reported in any of the included trials. The ongoing pregnancy rate was only available for one trial that compared immediate ambulation with 30 minute bed rest, with no evidence of an effect with bed rest (OR 1.00; 95% CI 0.54 to 1.85).

Secondary outcomes were sporadically reported with the exception of clinical pregnancy rate, which was reported in all of the included trials. There was no significant difference between less bed rest and more rest (OR 1.13; 95% CI 0.77 to 1.67). Nor was there any significant difference between the use of a fibrin sealant and control (OR 0.98; 95% CI 0.54 to 1.78). Even so, there was a significantly higher probability of pregnancy following mechanical closure of the cervix compared with no intervention (OR 1.92; 95% CI 1.40 to 2.63).

The risk of bias of the included studies was variable. The reporting of a proper method of randomisation and allocation concealment was demonstrated in the majority of trials, while only one trial was reported to be blinded.

Authors' conclusions

There is insufficient evidence to support a certain amount of time for women to remain recumbent following ET, or to support the use of fibrin sealants. Finally, there is limited evidence to support the use of mechanical closure of the cervical canal following ET. Further well-designed and powered studies are required to determine the true effect, if any, of these and other post ET techniques for women undergoing IVF and ICSI.

Plain language summary

In recent years assisted reproduction has become more evidence based in an attempt to determine what techniques truly work compared to what does not. This has led to major changes in the way embryos are transferred and what therapies are given to women before and after the transfer. Even so, one aspect that is still not well established is whether or not there are ways to decrease the movement or expulsion of embryos from the uterus following transfer. Based on this lack of information, combined with the need to clearly improve outcomes by reducing the risk of losing embryos following transfer, we decided to systematically locate and review the best available evidence regarding post-embryo transfer (ET) interventions for women undergoing IVF and intracytoplasmic sperm injection (ICSI). Following meticulous searches of major databases and conference proceedings we were able to locate four trials. These were all prospective, randomised controlled trials comparing two competing post-ET interventions or an intervention versus no treatment on clinical outcomes in women undergoing IVF and ICSI.

Our primary outcome measure, live birth rate, was not reported in any of the included trials. In addition, the ongoing pregnancy and or live birth rate was only reported in one trial that compared immediate ambulation to 30 minutes of bed rest following embryo transfer, with no clear difference reported. Clinical pregnancy rate was reported in all 4 trials. It was not clearly affected by different amounts of bed rest (more and less) following embryo transfer, nor was there any significant difference between the use of a fibrin sealant and no intervention. Forcibly closing the cervix resulted in a significantly higher chance of pregnancy compared with no intervention. The reporting of a proper method of randomisation and allocation concealment was demonstrated in the majority of trials, while only one trial was reported to have used blinding. In conclusion, there is insufficient evidence to support any certain amount of time for women to remain recumbent, if at all, following embryo transfer. Also there is insufficient evidence to support the addition of fibrin sealants to the embryo transfer media. Finally, there is limited evidence to support the use of mechanical pressure to close the cervical canal following embryo transfer. Further well-designed and powered studies are required to determine the true effect, if any, of post ET interventions on women undergoing IVF and ICSI.